PLANT PROTECTION 1 – Pests, Diseases and Weeds

PLANT PROTECTION 1 – Pests, Diseases and Weeds
Growers sending fruit interstate and overseas.
– Must comply with the Conditions of Entry
restrictions of the receiving State or Country. These
indicate the required treatments or inspections for
fruit fly. A guarantee of fruit fly-free status may be
achieved by quarantine and phytosanitary measures.
Many countries have a nil tolerance. Outbreaks of
papaya fruit fly in Australia caused NZ to ban
imports of Australian bananas – lifting the ban was
conditional on the bananas being harvested, packed
and exported in the unripe mature-green state.
– Must contact their nearest Department of
Agriculture/Primary Industry about required postharvest
treatments/inspection procedures.
– Search for exotic fruit flies www.daff.gov.au/aqis
Physical & mechanical methods.
Postharvest. Fruit may be disinfested by heat,
eg hot water dipping and circulating hot air, by
cold disinfestation treatments and irradiation.
Exclusion products. Mesh enclosures (about
2 mm diameter) exclude fruit flies, some other
insect pests, and birds. High value ripening fruit,
eg avocado, grapes, can be bagged by gardeners
and growers, eg PestGuard Bags, Fruit Sleeves.
Insecticides.
Fruit on trees. Control adults using cover
and/or bait sprays after monitoring, they are
compulsory by law in most States/Territories.
– Cover sprays, eg dimethoate, are usually systemic
insecticides that are applied to the whole tree to kill
the various stages of fruit fly (adults, eggs and larvae
present in fruit). On some crops, fruit flies are
controlled by insecticide sprays used against other pests.
Penetrant sprays, eg fenthion, are effective in
areas where baits are not. Sprays quickly kill adult
flies on foliage and fruit, and eggs and just hatched
maggots immediately under the skin of the fruit.
Table 4. Fruit flies – Some lures and insecticides.
What to use?
TRAPS TO DETECT AND MONITOR ADULTS
TRAPS - LURE MINUS INSECTICIDE
Fly Bye Fruit fly lure, Wild May fruit fly attractant (4-(p-hydroxyphenyl)-2-
butanone acetate) attract and kill male QFF
Many recipes for home made wet traps, eg
2 L water + half cup sugar +1 teaspoon of imitation vanilla essence + 2
tablespoons cloudy ammonia, hang 2 bottles in each tree as soon as trees
are in bloom. Household products, eg vegemite, marmite, sugar)
Insectrap is a non-toxic, sticky, yellow trap that attracts and traps
Diptera insects, it also traps citrus gall wasps.
TRAPS – LURE PLUS INSECTICIDE
Different lures/insecticides are used in different traps
.Group 1B, eg
Biolure + maldison attracts female Medfly
Capilure + dichlorvos attracts male Medfly, QFF, papaya fruit fly
Dak pot Lure & Insecticide (maldison) Trap, Q-Fly Lure, Searles Fruit
Fly Wick Attractant, Eco-naturalure attract male QFF
Methyl eugenol + maldison attracts many exotic male fruit flies
Trimedlure + insecticide attracts male Medfly
Group 2B, eg
Cue-lure + fipronil attracts male QFF, lesser QFF, some exotic
species, attracts male within radius of 400 meters or more.
Wet or food traps (protein or sugar + insecticide) attracts both male
and female Medflies, other flies as well.
FOLIAGE BAITING (LURE PLUS INSECTICIDE)
Group 1B, eg Dak-pot fruit Fly Attractant (yeast, for use with a suitable
insecticide, usually maldison). State/territories provide specific
information on foliage baiting.
Group 5, eg Eco-naturalure Fruit Fly Bait Concentrate, Naturalure Fruit Fly
Bait Concentrate, Yates Nature Way Fruit fly (protein/sugar-based
bait + spinosad), controls fruit flies including QFF and Medfly.
COVER SPRAYS
Group 1B, eg chlorpyrifos, dimethoate, fenthion, maldison,
trichlorfon)
POSTHARVEST DIPPING OF FRUIT
Group 1B, eg dimethoate, fenthion
72 Insects and allied pests - Diptera (flies)
Disadvantages of cover sprays.
May be very disruptive to parasites and predators.
Their use may increase other pests.
Do not prevent adults laying eggs in the fruit. Egg
laying punctures may be unacceptable blemishes.
Lebaycid (fenthion) is very toxic to birds.
Some sprays, eg Rogor (dimethoate) may cause
leaf and fruit drop in apricots and early peaches
–Protein bait sprays, a mixture of protein, water and
insecticide, can be spot sprayed onto trees and other
sites in an orchard. Protein attracts both male and
female fruit flies which are killed as they feed.
Female fruit flies require protein for egg laying and
are especially attracted. Baiting is more effective
when carried out in the morning when fruit flies are
active. Mark trees which have been bait sprayed.
Advantages of bait sprays
Effective against both male and female fruit flies.
Applied to foliage or boards, not fruit. Less costly.
Less disruptive to natural controls, honey bees.
Only small quantities of insecticide are used.
Helicopters can be used to over wide areas.
Most effective in isolated or semi-isolated areas
for orchard or community baiting schemes.
Not all trees may need to be treated.
Disadvantages of bait sprays
Only kills adult flies, does not prevent development
of eggs and maggots already in the fruit. If fruit is
infested supplementary cover sprays may be needed.
May not provide adequate control under high fly
pressure or in highly susceptible crops.
Are applied more frequently than cover sprays.
Less effective for a few trees or in orchards near
urban areas with high fruit fly populations.
Not rainfast, re-application is necessary after heavy
or continuous rain to maintain effectiveness.
May mark commercial fruit, eg mango.
Fruit postharvest may need disinfestation to
comply with quarantine regulations.
Comments
Traps are used to detect and monitor the presence of
fruit flies in an area so that baits or cover sprays may be
timed precisely. Lures used to attract adult fruit flies
include pheromones, food (protein/sugar) or coloured
spheres coated with a sticky gel (blue best for QFF and
yellow for Medfly). Depending on the type of trap
used, flies get caught on a sticky surface, killed by
insecticide, dehydrate or drown in liquid bait.
Lure plus insecticide traps for detection/monitoring
are used in conjunction with a baiting program or cover
sprays (or a combination of both) to effect control of the
targeted fruit fly. Regular monitoring of the crop for egglaying
by female flies should be employed in addition to
the use of lures. These traps are a mixture of usually a
male attractant (pheromone or food attractant) and an
insecticide to kill the attracted fruit fly. Lures are usually
placed in trees and can be applied as gels, impregnated
fibre board blocks, absorbent wicks and strings or traps,
placed at high densities in the areas where the targeted
species is known to occur. The aim is to reduce the
populations to such an extent that no mating occurs, but
their main function is monitoring. They do not satisfy
quarantine regulations. May be used in area-wide
management strategies.
Foliage baits are a mixture of a food attractant and an
insecticide. Both male and female fruit flies are attracted
and die after coming in contact with the insecticide or
ingesting it. Follow label instructions on where and
when to apply, etc. Wash all fruit after harvest to remove
any residues. Foliage baiting may not be as effective as
cover spraying under severe pest pressure or frequent rain.
Must be applied more often.
Cover sprays are used to spray the entire tree (foliage/
fruit) to kill fruit flies resting in the tree, maggots and eggs
in the fruit. Time of application varies with species, other
insects present at time of spraying will be killed.
There may be dipping requirements for commercial
certification of produce against fruit flies.